1. Field of the Invention
The invention relates to a tape printing apparatus for printing desired characters such as letters and symbols onto a tape, and more particularly, to a tape printing apparatus of a type capable of printing characters onto a tape so that the characters may be aligned along a longitudinal direction of the tape.
2. Description of the Related Art
U.S. Pat. No. 5,061,152 has proposed a tape printing apparatus, in which a font ROM incorporated in its controller stores dot pattern data of plural classes of character sizes. An operator operates the tape printing apparatus to input characters such as letters and symbols desired to be printed on a tape (desired document) and to designate a character size, with which the characters are desired to be printed. In the present specification, various characters, such as alphanumeric characters and letters, i.e., alphabetic characters and letters ("a", "B" . . . , for example) and numeric characters ("1", "2", . . . , for example), other kinds of characters and letters, such as hieroglyph letters, various symbols, such as ".male.", ".female.", etc., and other kinds of various characters and letters to be printed on a tape are all referred to as "characters." The tape printing apparatus prints the inputted characters onto a tape (printing medium) which has a width of 10 mm, 24 mm, or the like so that the characters are aligned along the longitudinal direction of the tape. The tape printing apparatus is further provided with various editing functions.
The size of the characters constituting the document is restricted or limited by the width of the tape, onto which the document is desired to be printed. Accordingly, the operator has to designate the character size, dependently on the width of the tape to be printed with the desired characters.
Generally, in order to print alphabetic characters, including capital letters and small letters, onto a tape, a base line is defined to extend in the longitudinal direction of the tape. All the capital letters of alphabetic characters are printed to be aligned along the base line with their bottom points being located on the base line. In other words, an entire part of each of the capital letters is located just on the base line, and no part of the capital letter protrudes down from the base line. Similarly, some of the small letters, such as "a" and "b", are printed to be aligned along the base line with their bottom being located on the base line to have no part protruding down from the base line. These small letters and capital letters are referred to as "non-protruding characters," hereinafter. Some other small letters, such as "g" and "j", are printed to be aligned along the base line with their bottom portions protruding down from the base line. These letters will be referred to as "protruding characters," hereinafter.
Conventionally, in order to print alphabetic characters onto a tape, the base line is defined to be located in a position close to but somewhat lowered from the center of the width of the tape, regardless of the designated character size, in order that the protruding characters can be properly printed together with the capital letters and the non-protruding characters.